/Engine/Plugins/Online/OnlineSubsystemNull/Source/Public/OnlineSubsystemNull.h
Exec handler that allows the online subsystem to process exec commands
true if the handler consumed the input, false to continue searching handlers
virtual bool Exec ( class [UWorld](API\Runtime\Engine\Engine\UWorld) * InWorld, const TCHAR * Cmd, [FOutputDevice](API\Runtime\Core\Misc\FOutputDevice) & Ar )